Hydraulic steering systems for ships



July 5, 1%66 D. GILMORE 3,259,095

HYDRAULIC STEERING SYSTEMS FOR SHIPS Filed March 22, 1965 United States Patent 3,259,095 HYDRAULIC STEERING SYSTEMS FOR SHIPS Frederic David Gilmore, Woolwich, Maine, assignor to Hyde Windlass Company, Division of Bath Iron Works Corporation, Bath, Maine, a corporation of Maine Filed Mar. 22, 1965, Ser. No. 441,527 11 Claims. (Cl. 114-150) This invention relates to hydraulic steering systems for ships and more particularly to a novel follow-up mechanism for use in such systems.

In a ship steering system of the type with which the present invention is concerned, operating means, such as a hydraulic piston and cylinder operator run by a variable delivery pump, is provided for angularly rotating the ships rudder in response to movement of an appropriate steering control such as a wheel. A follow-up mechanism is commonly provided for automatically stopping the rudder stock in a desired displaced position proportional to a displacement of the steering wheel. Frequently this is accomplished by the utilization of a differential or the like mechanism to which is connected the steering wheel, the follow-up mechanism and the variable displacement pump, such that the follow-up mechanism provides to the variable displacement pump, connected to it through the differential mechanism, a restoring movement equal and opposite to that initially applied to it by a displacement of the steering wheel, in order to stop the pump delivery when there has occurred any given desired rudder displacement proportional to that of the steering wheel.

However, in order that the restoring movement be truly equal, it is vital that lost motion in the follow-up mechanism be eliminated. The failure to accomplish this in heretofore known mechanisms, particularly in their inability to be readily and easily compensated for wear, has been a serious problem.

Accordingly, it is a major object of the present invention to provide a novel follow-up mechanism in which the above mentioned problem is eliminated.

It is a particularly valuable feature of the follow-up mechanism of the invention that, not only is it less subject to wear than are heretofore known mechanisms, but wherein simple adjustments are incorporated to make possible the compensation for wear while the mechanism remains in fully assembled condition and even while in active use.

It is another object of the invention to provide a complete steering system for ships incorporating a novel follow-up mechanism as well as other novel mechanical arrangements.

To accomplish the above and still further objects, the invention provides novel follow-up means connected between the ships rudder stock and the differential mechanism to which is connected the rudder stock operating means and the steering control. Such follow-up means includes a tiller mounted at one end on the rudder stock movable in an arcuate path to accomplish rotative movement of said stock, a rotary member having a surface in the form of a flat helix connected to said differential, and connecting means therefor having a flat contact surface of limited longitudinal dimension relatively to said rotary member and extending transversely thereof in slidable contact with said surface of said rotary member for linear movement of said contact along the helix axis responsive to arcuate movement of said tiller to rotate said rotary member about said helix axis and operate the differential to decrease the displacement of the rudder stock following an initial displacement thereof by the steering control. For optimum operation, the connecting means includes a rotatable member having a pair of opposed contact jaws for slidably clamping opposite side surfaces of the rotary member therebetween, such jaws being mounted on said tiller for rotative movement about an axis parallel to and spaced from said rudder stock axis and for sliding radial movement along said tiller toward and away from said rudder stock axis providing for linear movement of said jaws along said helix axis responsive to arcuate movement of said tiller, and are relatively adjustable toward and away from one another for adjustment of their clearance to compenste for wear. Preferably, the hydraulic tiller actuator is connected to the rotatable member and guide means restraining said member for linear movement are also provided.

For the purpose of fully explaining the various objects and features of the invention, reference is now made to the following more detailed description of a preferred embodiment thereof, together with the accompanying drawings, wherein FIG. 1 is a plan view of apparatus according to the invention;

FIG. 2 is an isometric view of certain of the elements of the apparatus of FIG. 1;

FIG. 3 is a sectional view taken on the line 3-3 of FIG. 2, and

FIG. 4 is a sectio'hal view taken on the line 44 of FIG. 3.

In the drawings is shown the essentials of a ship steering system including a rudder stock 12 rotatable about a vertical axis 14 having a tiller 16 mounted at one end of said rudder stock, with its outer ends being movable in an arcuate path to produce rotative movement of said stock. The outer end of said tiller as shown is provided with slideways 18 providing an opening 20 therebetween, a slide block 22 being positioned in said opening for sliding movement along tiller 16 toward and away from the rudder stock axis 14. In slide block 22 is mounted a tiller connecting member 25 including a trunnion or rotary element 24 mounted for rotative movement relative to said slide block about an axis 26 parallel to and spaced from the rudder stock axis 14, such being guided for linear movement along a line perpendicular to and spaced from the rudder stock axis 14 by a fixed guide bar 27 mounted on frame 10 of the apparatus and slidably received in bore 28 of connecting member 25, restraining it from rotation. With a double ended tiller 16 as shown, such slideways 18, block 22 and member 24 are mounted at each end of said tiller.

For moving tiller 16, hydraulic operating means are provided, connected to each end of tiller 16, including piston rod 30 fixedly mounted in connecting member 25 and having its ends received in opposed hydraulic cylinders 32, 34. Said cylinders as shown on one outer end of tiller 16 are alternatively provided with pressurized fluid through their lines 33, 35, respectively, by a variable delivery pump 40 of a type known to the art having fluid supply and exhaust lines 41, 42, respectively, to fluid reservoir 44, and a rotary control shaft 46 for varying the delivery thereof reversibly to increase it in either direction from an off center position alternatively to deliver fluid under pressure either to line 33 or 35 and so move tiller 16 and rudder stock 12 in a desired direction. A duplicate pump 58 similarly operates the cylinders (not shown) on the other outer end of tiller 16. The desired movement of control shaft 46 of pump 40 or of control shaft 59 of pump 58 is provided by a steering control in the form of a wheel 50 or 51, respectively, manually or automatically operated as desired. Wheel 50 is connected through a conventional three shaft differential 54 to pump control shaft 46. Wheel 51 is connected to shaft 59 of pump 58 through a similar differential 56. The use of two pumps provides two entirely sparate hydraulic systems for most reliable operation.

For converting the linear motion of rotary element 24 to rotary motion for application to the third input shafts 55, 57, of differentials 54, 56, respectively, a pair of rotatably mounted helix members 60, 62 are provided, connected, respectively, as shown, to differential shafts 55, 57, such helix members being suitably mount d on frame for rotation about their respective helix axes 61, 63 which are in turn parallel to the axes of guide 27 and piston 30 and perpendicular to rudder stock axis 14 and rotary element axis 26, preferably equally spaced on each side of the latter. Each of said helix members 60, 62, has a pair of opposite, parallel, helically twisted side surfaces 64, 66, with a maximum helix angle of less than 30 degrees, preferably at about 10 degrees but in excess of 2 degrees, to its respective helix angles 61, 63, which axes are positioned between said surfaces and so extend in a direction perpendicular to and spaced from said rudder stock axis 14 adjacent the illustrated free end of tiller 16.

For connecting helix members 60, 62 to rotary element 24 is provided a pair of opposed contact jaws, including a lower jaw 70 carrying a pair of wear plates 71 and a pair of outwardly spaced alignment pins 73, 75, and having a central threaded bore 78 extending along axis 26. An upper jaw 80 carrying a pair of wear plates 81 is provided mounted on the lower jaw by means of its bores 83, 85, receiving alignment pins 73, 75, and a central bolt 90 passing through its srrfooth central bore 88. A compression spring 92 is interposed between jaws 70 and 80 around bolt 90 for accurate adjustment of helix members 60, 62, between wear plates 71, 81, to ensure linear movement of said jaws along said helix axis responsive to arcuate movement of said tiller. The jaws and their wear plates have flat contact surfaces of limited longitudinal dimension relatively to the rotary helix members and extending transversely thereof slidably and adjustably clamping the surfaces 64, 66 of said helix member therebetween.

In operation, then, this arrangement provides linear movement of the contact member jaws along the respective helix axes 61, 63, responsive to arcuate movement of tiller 16 which rotates the helix members 60, 62 about their said helix axes and operates differentials '54, 56 to decrease the delivery of variable delivery pumps 40 and 58 following an initial increase in their delivery by displacement of steering wheel 50. Adjustment for wear is provided for simply by taking up on bolt 90 so that a desired clearance is provided between the wear plates and the interposed helix members.

Otherwise, the operation is conventional, with steer- 1 ing wheel being operated to operate pump shafts 46 and 59 through differentials 54 or 56 to operate pumps 40 and 58 to energize one of cylinders 32, 34 and their corresponding cylinders on the other outer end of tiller 16 to initiate angular movement of tiller 16 and rudder stock 12. Such angular movement, by means of the follow-up mechanism as explained above, in turn produces an equal and opposite movement of pump shafts 46 and 59 and so cuts off further flow of pressurized fluid to the connecting pistons, stopping movement of tiller 16 and rudder stock 12 at the desired angular displacement thereof.

Thus it will be seen that the invention provides novel ship steering systems with novel follow-up systems having unique advantages over those heretofore known. Various modifications of the invention within the spirit thereof and the scope of the appended claims will be apparent to those skilled in the art.

What is claimed is:

1. In a ship steering system including a rudder stock rotatable about an axis and operating means therefor,

differential means connected to said operating means angularly to displace said stock and a steering control connected to said differential,

that improvement which consists of:

follow-up means connected between said rudder stock and said differential, said follow-up means including a tiller mounted on said rudder stock and movable in an arcuate path to effect rotative movement of said stock,

a rotary member connected to said differential, said rotary member having a helically twisted flat surface and mounted for rotation about a helix axis extending in a direction perpendicular to and spaced from said rudder stock axis adjacent the outer end of said tiller and connecting means including a contact member mounted on said outer end of said tiller for linear movement of said contact member along said helix axis responsive to arcuate movement of said tiller,

said contact member having a flat contact surface of limited longitudinal extent relatively to said rotary member and extending transve'resly thereof in sliding contact with said surface of said rotary member for linear movement of said contact member along said helix axis responsive to arcuate movement of said tiller to rotate said rotary member about said helix axis and operate said differential to decrease the displacement of said stock following an initial displacement thereof by said steering control.

2. In a ship steering system as claimed in claim 1 wherein the maximum helix angle of said rotary member surface is less than 30 degrees. I

3. In a ship steering system including a rudder stock rotatable about an axis and operating means therefor,

differential means connected to said operating means angularly to displace said stock and a steering control connected to said differential,

that improvement which consists of:

follow-up means connected between said rudder stock and said differential, said follow-up means including a tiller mounted on said rudder stock and movable in an arcuate path to effect rotative movement of said stock,

a rotary member connected to said differential, said rotary member having a pair of opposite parallel helically twisted side surfaces and mounted for rotation about a helix axis positioned between said surfaces and extending in a direction perpendicular to and spaced from said rudder stock axis adjacent the outer end of said tiller and connecting means including a pair of opposed contact jaws mounted on said outer end of said tiller for linear movement of said jaws along said helix axis responsive to arcuate movement of said tiller,

said jaws having flat contact surfaces of limited longi tudinal extent relatively to said rotary member and extending transversely thereof slidably clamping said surface of said rotary member therebetween for linear movement of said contact member jaws along said helix axis responsive to arcuate movement of said tiller to rotate said rotary member about said helix axis and operate said differential to decrease the displacement of said stock following an initial displacement thereof by said steering control.

4. In a ship steering system as claimed in claim 3 wherein said jaws are mounted for adjustable movement toward and away from one another for setting the clearance therebetween.

5. In a ship steering gear system including a rudder stock rotatable about an axis and hydraulic operating means therefor including a variable delivery p p,

rotary differential means connected to said pump effective to vary the delivery thereof and a steering control connected to said differential that improvement which consists of follow-up means connected between said rudder stock and said differential, said follow-up means including a tiller mounted on said rudder stock and movable in an arcuate path to effect rotative movement of said stock a rotary member connected to said differential, said rotary member having a pair of opposite parallel helically twisted side surfaces at a maximum angle of less than 30 degrees to the helix axis and mounted for rotation about said helix axis positioned between said surfaces and extending in a direction perpendicular to and spaced from said rudder stock axis adjacent the outer end of said tiller connecting means including a pair of opposed contact jaws mounted on said outer end of said tiller for rotative movement about an axis parallel to and spaced from said rudder stock axis and for sliding movement along said tiller toward and away from said rudder stock axis for linear movement of said tiller,

said jaws having relatively adjustable fiat contact surfaces of limited longitudinal extent relatively to said rotary member and extending transversely thereof slidably clamping said surfaces of said rotary member therebetween for linear movement of said contact member jaws along said helix axis responsive to arcuate movement of :said tiller to rotate said rotary member about said helix axis and operate said differential to decrease the delivery of said variable delivery pump following an initial increase in said delivery by displacement of said steering control.

6. In a ship steering system as claimed in claim 5 wherein.

a pair of said rotary members and said differentials are provided, the axes of said rotary members being spaced radially inwardly and outwardly of the axis of rotative movement of said connecting. means.

7. In a ship steering system as claimed in claim 6 wherein said jaws extend across said pair of rotary members and are provided with central adjusting means extending along said axis of rotative movement of said connecting means.

8. In a ship steering gear system including a rudder stock rotatable about an axis a tiller mounted on said rudder stock and movable in 4 an arcuate path to effect rotative movement of said stock and a steering control that improvement which consists of operating means connected between said tiller and said steering control, said operating means including connecting means including a rotary tiller connecting member mounted on said outer end of said tiller for rotative movement about an axis parallel to and spaced from said rudder stock axis and for sliding movement along said tiller toward and away from said rudder stock axis for linear movement responsive to arcuate movement of said tiller,

guide means restraining said connecting means for said linear movement,

tiller power operating means including hydraulic prime mover means connected to said rotary tiller connecting member and a variable delivery pump therefor,

tiller follow-up means including a rotary member having a pair of opposite parallel helically twisted side surfaces at a maximum angle of less than 30 degrees to the helix axis and mounted for rotation about a helix axis positioned between said surfaces and extending in a direction perpendicular to and spaced from said rudder stock axis adjacent the outer end of said tiller and a pair of opposed contact jaws mounted on said rotary connecting member,

said jaws having relatively adjustable flat contact surfaces of limited longitudinal extent relatively to said rotary member and extending transversely thereof slidably clamping surfaces of said rotary member therebetween for linear movement of said contact member jaws along said helix axis responsive to arcuate movement of said tiller to rotate said rotary member about said helix axis and rotary differential means connected to said steering control, to said rotary member and to said pump effective to vary the delivery thereof, said rotary member operating said differential means to decrease the delivery of said variable delivery pump following an initial increase in said delivery by displacement of said steering control.

9. In a ship steering system as claimed in claim 8 wherein a pair of said rotary members and said differentials are provided, the axes of said rotary members being spaced radially inwardly and outwardly of the axis of rotative movement of said connecting means, and wherein said jaws extend across said pair of rotary members and are provided with central adjusting means extending along said axis of rotative movement of said connecting means.

10. In a ship steering system as claimed in claim 9 wherein said angle of said surfaces is about 10 degrees.

11. In a ship steering system as claimed in claim 8 wherein is provided a variable delivery pump connected to each of said differentials providing a pair of independent hydraulic systems for operating said tiller.

No references cited.

MILTON BUCHLER, Primary Examiner.

A. H. FARRELL, Assistant Examiner. 

1. IN A SHIP STEERING SYSTEM INCLUDING A RUDDER STOCK ROTATABLE ABOUT AN AXIS AND OPERATING MEANS THEREFOR, DIFFERENTIAL MEANS CONNECTED TO SAID OPERATING MEANS ANGULARLY TO DISPLACE SAID STOCK AND A STEERING CONTROL CONNECTED TO SAID DIFFERENTIAL, THAT IMPROVED WHICH CONSIST OF: FOLLOW-UP MEANS CONNECTED BETWEEN SAID RUDDER STOCK AND SAID DIFFERENTIAL, SAID FOLLOW-UP MEANS INCLUDING A TILLER MOUNTED ON SAID RUDDER STOCK AND MOVABLE IN AN ARCUATE PATH TO EFFECT ROTATIVE MOVEMENT OF SAID STOCK, A ROTARY MEMBER CONNECTED TO SAID DIFFERENTIAL, SAID ROTARY MEMBER HAVING A HELICALLY TWISTED FLAT SURFACE AND MOUNTED FOR ROTATION ABOUT A HELIX AXIS EXTENDING IN A DIRECTION PERPENDICULAR TO AND SPACED FROM SAID RUDDER STOCK AXIS ADJACENT THE OUTER END OF SAID TILLER AND CONNECTING MEANS INCLUDING A CONTACT MEMBER MOUNTED ON SAID OUTER END OF SAID TILLER FOR LINEAR MOVEMENT OF SAID CONTACT MEMBER ALONG SAID HELIX AXIS RESPONSIVE TO ARCUATE MOVEMENT OF SAID TILLER, SAID CONTACT MEMBER HAVING A FLAT CONTACT SURFACE OF LIMITED LONGITUDINAL EXTENT RELATIVELY TO SAID ROTARY MEMBER AND EXTENDING TRANSVERSELY THEREOF IN SLIDING CONTACT WITH SAID SURFACE OF SAID ROTARY MEMBER FOR LINEAR MOVEMENT OF SAID CONTACT MEMBER ALONG SAID HELIX AXIS RESPONSIVE TO ARCUATE MOVEMENT OF SAID TILLER TO ROTATE SAID ROTARY MEMBER ABOUT SAID HELIX AXIS AND OPERATE SAID DIFFERENTIAL TO DECREASE THE DISPLACEMENT OF SAID STOCK FOLLOWING AN INITIAL THE DISPLACEMENT THEREOF BY SAID STEERING CONTROL. 